I'm asking here because I'm hoping someone who tinkers with game files and whatnot would know the answer to this question.

What exactly are the TF2 weapon kill icons made up of? .vtfs?

For the uninformed, FF's weapon kill icons (you know, stuff like Skanky KNIFE Ihmhi) are basically a font. That's how it was in many Source games and most HL games/mods. But nowadays, TF2 has all these fancy colors and stuff in their icons, and as far as I'm awares a font can only be one color. So how the heck do they do it?